How to correct Normals for DupliVerts?
Place the pillar at the beginning of the curve, be sure to apply rotation and scale (or at least have an alignment relative to the world or the object itself, locally)  :



Parent the pillar to the curve, and set dupli as frames (uncheck the speed button) :



For the curve, set it to path animation tunes the frame count (it will be the amount of pillars) and check 'follow'.



Now add a constraint to the pillar to 'limit rotation', and check the wanted axis (here Y). So the pillar will follow the curve without rotating around this axis.